Born to the French nobilty; brother of a viscount of Narborne; uncle of the queen of Navarre. Joined the Mercedarians. Sent to Constantinople to ransom two imprisonedMercedarian brothers, Ottone was immediately imprisoned himself. When sultan Bajazet II learned that Ottone was a member of the nobility, he had the prisoner brought to him and asked why he had not brought it up to obtain better treatment; Ottone explained that he had abandoned worldly titles to serve Christ, and began explaining Christianity. The sultan had him thrown back into his cell and then murdered. Martyr.